Over the years I've had the necessity to add humidity to my plant area and have used the stone/water humidity trays under the plant stands with good success.The only issue is how to keep them clean and free of the slime that accumulates in them over time.Is there a product or that I can at to the water to inhibit the growth of that stuff in my trays?

djlen wrote:How do you keep them from turning into a swamp with algae etc.?Over the years I've had the necessity to add humidity to my plant area and have used the stone/water humidity trays under the plant stands with good success.The only issue is how to keep them clean and free of the slime that accumulates in them over time.Is there a product or that I can add to the water to inhibit the growth of that stuff in my trays?

How do you know you have had success if you don't have a humidity gauge? Your success may be due to other factors. I think you will have identical results if you remove the stones and just leave the water that drains into the tray when you water. It will be a lot easier to clean. A few drops of pool algaecide or Physan will keep down the algae. I usually don't bother unless I am expecting orchid or bonsai company. During the summer, when all the plants are outdoors, I soak the trays in a strong bleach solution & have them scrubbed by the cleaning woman or granddaughter.Iris

You mean you can get your Grand-babies to do that for you??!!!???? Wow!!!!

Actually, the last time I used the trays I did have a hydrometer and could keep the room at around the 50%area. I thought this was pretty good with the heat we have. The plants seemed to like it as well.We do have that Physan!!! Your mentioning it reminded me that we have some and we will use that for keepingthe algae at bay. I will be using those seed flats for the water (I won't be using stone...just another thing to clean. They measure about 12" X 21" and about 2" deep. How much Physan should I be using to be effective in a flat of that size, Iris?Thank you again!

50% humidity may not be enough for Podocarpus. Small ones are used for terrarium plants. Do you grow Serissa or Fukien tea successfully?The Physan bottle should tell you how much to use. Try a teaspoon in a tray. It works slowly.Iris

For the last two years I have been using humidity trays with top grids which lift the bonsai out of the water. The trees still need air circulation under the pot which won't happen if they're sitting in a tray of water. These trays are sold by online orchid dealers and are worth the cost. As far as I'm concerned humidity is not the goal but catching the runoff is the purpose I use them.

I'm having the same problem as you with the standing runoff in the trays and algae growth especially with the tropicals under HID lights. The room is very hot , humid and bright. I've been using an old turkey baster to suck up the standing water but it would be helpful to have something to control the algea. I was wondering about Physan .... I'm glad you suggested this , Iris.

Yes, I have two Fukiens and a few Serissa and all are doing well. The leaves of the Podocarpus are uncurling as we speak. Really!! I have compared them to the pictures I took earlier and they are responding.....I'm not sure whether the Safer's spray did it or the flush I gave it in the kitchen sink. But it's looking much better.I will check the directions on the bottle of the Physan and figure out what will do it.

Hi Norma - I don't stand the plants in the water. That would be a disaster with most of them. I am using the water trays under the plant stand strictly as a humidifier. This has worked for me in the past. I'm holding in the high 40's for humidity currently. All the plants are happy and the hopefully the Podocarpus will continue to respond. I'm finding that it likes more water than I'd originally thought......which may have been a contributing factor.BTW Norma, Physan worked for us very well when we used it previously.